Absorbent device using an apertured nonwoven as an acquisition distribution layer

ABSTRACT

An absorbent article having a topsheet, an intermediate layer, an absorbent core, and a backsheet, wherein the intermediate layer is formed of an apertured nonwoven. The intermediate layer may include stiffening means such as apertured film or an additional nonwoven layer.

RELATED APPLICATIONS

This application is a continuation-in-part of application Ser. No.10/308,312, filed Dec. 2, 2002 now U.S. Pat. No. 6,849,319, which claimsthe benefit of provisional Application No. 60/336,918 filed Dec. 3, 2001and a continuation-in-part of application Ser. No. 10/783,428, filedFeb. 20, 2004 now U.S. Pat. 7,204,907, which is a continuation-in-partof application Ser. No. 10/308,312 filed Dec. 2, 2002 now U.S. Pat. No.6,849,319, which claims the benefit of provisional Application No.60/336,918 filed Dec. 3, 2001.

TECHNICAL FIELD

This invention relates to absorbent articles, and more particularly tointermediate layers of absorbent articles.

BACKGROUND

Modern absorbent articles are typically comprised of four basic layers:a topsheet, an absorbent core, an intermediate layer between thetopsheet and the absorbent core, and a backsheet opposite the topsheet.Several design criteria affect the choice of materials for these layers.Both nonwovens and apertured films are used as topsheets, each havingadvantages and disadvantages. Absorbent cores may be made of manydifferent combinations of materials, including pulp and other fibrousmaterials as well as super absorbent particles or fibers. Backsheets aretypically made of films; sometimes breathable materials may be used, butthe primary concern is that the backsheet remain impervious to fluidleakage. Intermediate layers are a more recent addition to the absorbentarticle market.

In the past, absorbent articles may have contained nonwoven materialsbetween the topsheet and the absorbent core to reduce rewet from theabsorbent core to the surface. Recently, intermediate layers ofthree-dimensional formed film have proven exceptionally successful atpreventing rewet as well as increasing strikethrough performance andmasking performance.

SUMMARY

In an absorbent article having a topsheet and an absorbent core, athree-dimensional, apertured, non-woven material is positioned betweenthe topsheet and the absorbent core to improve the strikethrough, rewet,and fluid distribution characteristics of the absorbent article. Thethree-dimensional, apertured, nonwoven material may be a single layer ofnonwoven material, multiple layers of nonwoven material, or a layer ofnonwoven material combined with an apertured film.

The details of one or more embodiments of the invention are set forth inthe accompanying drawings and the description below. Other features,objects, and advantages of the invention will be apparent from thedescription and drawings, and from the claims.

DESCRIPTION OF DRAWINGS

FIG. 1 is a cross sectional view of a first embodiment of the absorbentarticle of the invention.

FIG. 2 is a cross sectional view of a second embodiment of the absorbentarticle of the invention.

FIG. 3 is a cross sectional view of a third embodiment of the absorbentarticle of the invention.

FIG. 4 is a cross sectional view of the method for manufacturing acomposite topsheet.

FIG. 5 is a cross sectional view of a fourth embodiment of the absorbentarticle of the invention.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION Definitions

As used herein, the term “substantially” means that a given property orparameter may vary by about 20% from the stated value.

As used herein, the term “absorbent article” means articles that absorband contain body exudates. More specifically, the term refers toarticles that are placed against or in proximity to the body of a wearerfor absorbing and containing various exudates discharged from the body.For example, “absorbent article”, as used herein, includes diapers,incontinent articles, sanitary napkins, pantiliners, bandages, and otherarticles used to absorb body exudates.

The term “diaper” refers to a garment typically worn by infants andincontinent persons that is drawn up between the legs and fastened aboutthe waist of the wearer. Examples of diapers from the prior art includediapers described in U.S. Pat. Re. No. 26,152, issued to Duncan, et al.on Jan. 31, 1967; U.S. Pat. No. 3,860,003 issued to Buell on Jan. 14,1975; U.S. Pat. No. 4,610,678 issued to Weisman, et al. on Sep. 9, 1986;U.S. Pat. No. 4,673,402 issued to Weisman, et al. on Jun. 16, 1987; U.S.Pat. No. 4,695,278 issued to Lawson on Sep. 22, 1987; U.S. Pat. No.4,704,115 issued to Buell on Nov. 3, 1987; U.S. Pat. No. 4,834,735issued to Alemany, et al. on May 30, 1989; U.S. Pat. No. 4,888,231issued to Angstadt on Dec. 19, 1989; and U.S. Pat. No. 4,909,803 issuedto Aziz, et al. on Mar. 20, 1990.

The term “incontinent article” refers to pads, undergarments, e.g., padsheld in place by a suspension system, such as a belt, or other device,inserts for absorbent articles, capacity boosters for absorbentarticles, briefs, bed pads, and similar devices, whether worn by adultsor other incontinent persons. Examples of incontinent articles includethose disclosed in U.S. Pat. No. 4,253,461 issued to Strickland, et al.on Mar. 3, 1981; U.S. Pat. Nos. 4,597,760 and 4,597,761 issued to Buell;the above-mentioned U.S. Pat. Nos. 4,704,115; 4,909,802 issued to Ahr,et al.; U.S. Pat. No. 4,964,860 issued to Gipson, et al. on Oct. 23,1990; and in U.S. patent application Ser. Nos. 07/637,090 and 07/637,571filed respectively by Noel, et al. and Feist, et al. on Jan. 3, 1991.

The term “pantiliner” refers to absorbent articles that are less bulkythan sanitary napkins that are generally worn by women between theirmenstrual periods. Examples of pantiliners are disclosed in U.S. Pat.No. 4,738,676 entitled “Pantiliner” issued to Osborn on Apr. 19, 1988.

The term “sanitary napkin” refers to an article that is worn by a femaleadjacent to the pudendal region that is intended to absorb and containvarious exudates that are discharged from the body, e.g., blood, menses,and urine. Examples of sanitary napkins are disclosed in U.S. Pat. No.4,285,343, issued to McNair on Aug. 25, 1981; U.S. Pat. Nos. 4,589,876and 4,687,478, issued to Van Tilburg on May 20, 1986 and Aug. 18, 1987respectively; U.S. Pat. Nos. 4,917,697 and 5,007,906 issued to Osborn,et al. on Apr. 17, 1990 and Apr. 16, 1991, respectively; and U.S. Pat.Nos. 4,950,264, and 5,009,653 issued to Osborn on Aug. 21, 1990 and Apr.23, 1991, respectively; and in U.S. patent application Ser. No.07/605,583 filed Oct. 29, 1990 in the name of Visscher, et al.

Throughout this description, the expressions “topsheet” and “backsheet”denote the relationship of these materials or layers with respect to theabsorbent core. It is understood that additional layers may be presentbetween the absorbent core and the topsheet and backsheet, and thatadditional layers and other materials may be present on the sideopposite the absorbent core from either the topsheet or the backsheet.

As used herein, the term “formed film” refers to a resilient threedimensionally formed film similar in structure to that produced byvacuum forming processes, as described in U.S. Pat. No. 4,456,570 toThomas or U.S. Pat. No. 3,929,135 to Thompson, among others.

As used herein, the term “non-woven web” refers to a web that has astructure of individual fibers or threads that are interlaid, but not inany regular, repeating manner. Non-woven webs have been, in the past,formed by a variety of processes such as, for example, meltblowingprocesses, spunbonding process, and bonded carded web processes.

As used herein, the term “meltblown fibers”, refers to fibers formed byextruding a molten thermoplastic material through a plurality of fine,usually circular, die capillaries as molten threads or filaments into ahigh velocity gas (e.g., air) stream that attenuates the filaments ofmolten thermoplastic material to reduce their diameter, which may be toa microfiber diameter. Thereafter, the meltblown fibers are carried bythe high velocity gas stream and are deposited on a collecting surfaceto form a web of randomly dispersed meltblown fibers.

As used herein, the term “stabilized” refers to a material of thepresent invention that is capable of being stored in a stable conditionin any common or conventional web storage manner without the need forfurther heating or the additional of or joinder with other webs tostabilize the material. Such storage means would include for example,low tension rolls or festooned material in boxes.

As used herein, the term “melt-stabilized” refers to portions of anonwoven web which have been subjected to localized heating and/orlocalized pressure to substantially consolidate the fibers of thenonwoven web into a stabilized film-like form.

As used herein, “pressure bonding” refers to a process in which a web isplaced between two elements that exert pressure on the web to bind thevarious components of the web in the area where pressure is beingexerted.

As used herein, the term “spunbonded fibers”, refers to small diameterfibers that are formed by extruding a molten thermoplastic material asfilaments from a plurality of fine, usually circular, capillaries of aspinneret with the diameter of the extruded filaments then being rapidlyreduced as by, for example, eductive drawing or other well-knownspunbonding mechanisms.

The term “finished absorbent article” is used herein to generally meanany absorbent article having incorporated all layers of material andother features that the article is intended to have that affect theproduct's performance characteristics. This term includes, but is notlimited to, products well known in the art as diapers, sanitary napkins,and adult incontinent briefs.

The term “insult” is used herein to refer to the act of applying afinite amount of liquid to the topsheet of a finished absorbent article.An insult may occur during product use and during finished producttesting. Consequently, “multiple insults” occur when the same finishedabsorbent article is insulted more than once. Multiple insults may occurduring product use and during finished product testing.

As used herein, “unconsolidated” means the fibers have some freedom ofmovement and are not fixed in position with respect to the other fibersin the web. In other words, the fibers generally are not compactedtogether or fused to the extent that an aperture cannot close, rather,the aperture may be blocked by some fiber strands that extend across,and partially obstruct it.

As used herein, “consolidated” means the fibers are generally compacted,fused, or bonded, so as to restrict movement of the fibers individually.Consolidated fibers will generally not extend out into an aperture andwill likely be more dense than unconsolidated fibers.

As used herein “mesh count” means the number of holes per squarecentimeter. Therefore a material with a higher mesh would have moreholes while a lower mesh would have fewer holes.

As used herein, the term “point bonding” means bonding one or morefabrics at a plurality of discrete points. For example, thermal pointbonding generally involves passing one or more layers to be bondedbetween heated rolls, for example, an engraved pattern roll and a smoothcalender roll. The engraved roll is patterned in some way so that theentire fabric is not bonded over its entire surface, and the calenderroll is usually smooth. As a result, various patterns for engraved rollshave been developed for functional as well as aesthetic reasons.

As used herein, “gsm” is an abbreviation for grams per square meter.

Absorbent Article Embodiments

Referring to FIG. 1, FIG. 2, FIG. 3, and FIG. 5, absorbent article 10has a body facing side 12. In use, the absorbent article 10 is typicallyplaced so that body facing side 12 faces the user's body and theopposite side of the absorbent article is either exposed, as in abandage, or faces the user's clothing, as in a diaper or femininehygiene product. Topsheet 13 is positioned on the body facing side 12 ofthe absorbent article and comprises a fluid pervious material to allowfluids to enter the absorbent article 10. Both nonwovens and aperturedfilms are typical materials used for topsheet 13. Backsheet 14 isopposite body facing side 12 and will typically be a fluid resistant orfluid impervious layer to prevent fluids from escaping the absorbentarticle 10. Absorbent core 16 will be between backsheet 14 and bodyfacing side 12 to absorb fluids. Intermediate layer 20 will be betweenabsorbent core 16 and body facing side 12. Intermediate layer 20 isdesigned to promote fluid flow from topsheet 13 to absorbent core 16while also preventing fluid flow from absorbent core to topsheet 13, asdiscussed in the background and in the testing section below.

In FIG. 1 and FIG. 2 the intermediate layer 20 has a resilient threedimensional formed film 22 with a male side 24 and a female side 26.Small scale apertures 28 in the formed film 22 have a mesh count ofbetween about 20/cm² and 200/cm². More preferably the mesh count of thesmall scale apertures is between about 50/cm² and 100/cm². Mostpreferably the mesh count of the small scale apertures is about 90/cm².Formed film 22 is preferably made of a thermoplastic material to aid informing. More preferably, formed film 22 is made of polypropylene,polyethylene, or some other polyolefin.

The resilient three-dimensional shape of the formed film 22 creates avoid volume on both the male side and the female side of the formed film22. It is advantageous in this invention to maintain that void volumeand not allow the absorbent core 16 or the fibers from the nonwoven web30 to fill the void volume. The void volume allows for efficient fluidtransfer both above and below the formed film 22. Therefore a lighttissue may be placed between the absorbent core and the intermediatelayer 20 to help in maintaining void volume of the intermediate layer.

A nonwoven web 30 is attached to the formed film 22, between the formedfilm 22 and topsheet 13. Nonwoven web 30 is preferably comprised offibers of polymeric material, although other fibers may be used. Inparticular, polypropylene and polyethylene, either alone or inbi-component and other blends, are effective.

A plurality of large scale apertures 32 extend through nonwoven web 30and formed film 22. The large scale apertures 32 have a mesh that isless than the mesh of the small scale apertures 28. The mesh count oflarge scale apertures 32 will preferably be between 2/cm² and 50/cm²,more preferably between 3/cm² and 30/cm², and most preferably between6/cm² and 11/cm². Therefore, the small scale apertures 28 will be morenumerous in a given area than the large scale apertures 32. An importantaspect of the large scale apertures 32 is to provide a three-dimensionalaspect to the intermediate layer 20.

In the preferred embodiments shown in FIG. 1 and FIG. 2, the large scaleapertures are generally conical, having a larger opening 34 and asmaller opening 36. In particular, the larger opening 34 is between thebody facing side 12 and the smaller opening 36. In a more preferredembodiment there are substantially unconsolidated fibers 38 near thelarger opening and substantially consolidated fiber 40 near the smalleropening.

In the preferred embodiments shown in FIGS. 1 and 2, it is possible forthe substantially consolidated fibers 40 and the formed film 22 to befused to create a point bond between the nonwoven web 30 and the formedfilm 22 at a plurality of the large scale apertures 32.

In the preferred embodiment shown in FIG. 1, the male side 24 of theformed film 22 is facing the nonwoven web 30. In contrast, FIG. 2 showsan embodiment where the female side 26 of the formed film 22 is facingthe nonwoven web 30.

In a preferred embodiment, the side of formed film 22 that is facing thenonwoven web 30, the male side 24 in FIG. 1 or the female side in FIG.2, is treated with a surfactant, and therefore is more hydrophilic.Typical surfactants would include non-ionic and silicone basedsurfactants, although others may be used.

As shown in FIG. 3, the intermediate layer 20 may include a stiffernonwoven layer 42 in the place of formed film 22. The stiffer nonwovenlayer 42 has a relatively rough texture, as compared to nonwoven web 30,and is formed of fibers with an average diameter larger than the fibersof nonwoven web 30. The stiffer nonwoven layer 42 is formed of materialssimilar to those used in nonwoven layer 30. The stiffer nonwoven layer42 may be a separate nonwoven web joined with nonwoven web 30 in amanner similar to formed film 22, or it may be a layer of fibers formedwith nonwoven web 30. The discussion above regarding the formation oflarge scale apertures 32 applies to the intermediate layer 20 of FIG. 3,with the stiffer nonwoven layer 42 replacing the formed film 22.

FIG. 1, FIG. 2, and FIG. 3 show composite versions of intermediate layer20. Each has a nonwoven web of fibers 30 and a stiffening means in theform of apertured film 22 or nonwoven layer 42. Other stiffening meansmay be selected from non-apertured films, less stiff nonwoven layers,woven layers, adhesive coatings, surfactant coatings, and othermaterials added to the nonwoven layer 30. In FIG. 5, intermediate layer20 is comprised of nonwoven web 30 with large scale apertures 32, butwithout a stiffening means.

Method for Making Intermediate Layers

A formed film 22 is manufactured to have a resilient three dimensionalstructure. The film is preferably manufactured by a vacuum formingprocess, wherein a molten layer of thermoplastic material is fed from amelt die onto a shaped screen utilizing vacuum pressure to form thethermoplastic material to the shape of the screen. Other methods formanufacturing resilient three dimensional formed films may includereheat processes.

A nonwoven web 30 is manufactured from polymeric fibers. In a preferredembodiment the nonwoven web is airthrough bonded, carded thermobonded,spunbonded, or spunbond meltblown spunbond. In a preferred embodimentthe fibers are single component or bi-component. In a preferredembodiment the material is polypropylene or polyethylene, althoughpolyester may be added.

The formed film 22 and nonwoven web 30 are joined prior to forming ofthe large scale apertures 32. In a preferred embodiment the formed film22 and the nonwoven web 30 are aligned adjacent each other. In anotherpreferred embodiment the formed film 22 is adhesively secured to thenonwoven web 30 prior to the forming of large scale apertures 32. Theimportance of joining the nonwoven web 30 with the formed film 22 is sothat large scale apertures 32 penetrate both the nonwoven web 30 and theformed film 22.

FIG. 4 shows a preferred mechanism for forming large scale apertures 32.A pin roll 50 and counter roll 52 rotate in opposite directions to forma nip through which the nonwoven web 30 and formed film 22 are fed. Pins54 protrude from the surface of pin roll 50. Holes 56 are recessed intocounter roll 52. Pin roll 50 and counter roll 52 are aligned so thatpins 54 mate with holes 56.

In a more preferred embodiment, pin roll 50 and counter roll 52 aremanufactured of rigid material and are mounted on an adjustable chassisto allow modification of the distance between the rolls. In particular,pin roll 50 is preferably manufactured of metallic material and pins 54are preferably manufactured of a metallic material. Pins 54 preferablyhave a pointed end and taper from about half of their length to thepointed end. In a preferred embodiment pins 54 are heated, as discussedin more detail below.

The holes 56 are preferably larger than pins 54 and are shaped. In apreferred embodiment the shape of holes 56 is partially replicated bythe large scale apertures 32. In a preferred embodiment the holes 54 aregenerally conical so that when the pins 54 push material into holes 56the material near the tips of pins 54 is compressed further than anyother material, and experiences more heat transfer if the pins 54 areheated. This preferred combination of narrow heated pins 54 andgenerally conical holes 56 produces a preferred large scale aperture 32having generally consolidated fibers 40 near a smaller opening 36 andgenerally unconsolidated fibers 38 near a larger opening 34.

In a less preferred embodiment counter roll 52 may be manufactured of apliable material, thereby making holes 56 unnecessary. In such anembodiment pins 54 would simply protrude into the pliable material ofcounter roll 52.

The pins 54 may be heated for several reasons. One reason to heat pins54 is to properly form large scale apertures 34. The heated pins 54 mayalso be heated to a temperature sufficient to bond the nonwoven web 30to the formed film 22. Furthermore, the heated pins 54 may help increating substantially consolidated fibers 40 near the smaller openings36. The pins may also be heated to provide for structural resilience inlarge scale apertures 32 in order to maintain void volume between theintermediate layer 20 and the absorbent core 16. In particular, theheated pins may cause the formed film 22 or the stiffer nonwoven layer42 to become more rigid and support the large scale apertures 32 duringfurther processing, storage, or use. This allows the use of a softernonwoven web 30 without compromising the shape of the large scaleapertures 32 or the void volume they create between the intermediatelayer 20 and the absorbent core 16.

In a first preferred embodiment the pins 54 are heated to a temperaturesufficient to fuse the consolidated fibers 40 and the formed film 22near the smaller openings 36, thus securing the nonwoven web 30 to theformed film 22. Even at this temperature, the shape of the pins 54 andthe holes 56 is such that unconsolidated fibers 38 still exist near thelarge openings 34.

In another preferred embodiment, the nonwoven web 30 is comprised ofmaterials with more than one melting point, such that a plurality offibers have a melting point near the melting point of the material offormed film 22, and lower than other fibers in the nonwoven web 30. Thepins 54 are heated to a temperature to melt the lower melting pointfibers and the formed film 22 near the smaller openings 36, thus formingconsolidated fibers 40 and securing the nonwoven web 30 to the formedfilm 22.

In yet another embodiment the fibers of the nonwoven web 30 have amelting point that is higher than the melting point of the material ofthe formed film 22. The pins 54 are heated to a temperature sufficientto melt the formed film 22 and bond the consolidated fibers 40 near thesmaller opening 36, thereby securing the nonwoven web 30 to the formedfilm 22.

In yet another embodiment the nonwoven web 30 is secured to the formedfilm 22 prior to forming the large scale apertures. Preferably thesecuring would be an adhesive bonding. In this embodiment the pins 54are heated to a temperature sufficient to shape the nonwoven web 30 inthe vicinity of the large scale apertures and form consolidated fibers40 near the smaller opening 36, but not necessarily enough to fuse theconsolidated fibers 40 to the formed film 22, or the formed film 22 tothe nonwoven web 30.

In yet another preferred embodiment the formed film any of the aboveexamples is replaced with a stiffer nonwoven layer 42 with similarmaterial characteristics.

In yet another preferred embodiment the nonwoven web 30 is run throughthe pins discussed above without a stiffening means 22, 42.

Finished Article Testing

The performance of several preferred embodiments of intermediate layer20 was evaluated in use on a Proctor & Gamble Petalo blu Core with anHFF topsheet. The preferred embodiments were compared against theperformance of a Procter & Gamble acquisition distribution layer (ADLabout 80 gsm).

The three embodiments tested were Type 14, Type 15, and Type 16,described below:

Type 14 is a spunbond/meltblown/spunbond 15 gsm nonwoven combined withan air-through bonded 25 gsm nonwoven.

Type 15 is a carded thermal-bonded philic 18 gsm nonwoven combined witha Tredegar three-dimensional apertured formed film with the male sidefacing the topsheet.

Type 16 is a single layer of carded airthrough bonded philic 18 gsmnonwoven.

The following table summarizes the results of the tests forstrikethrough, wetback, and partition coefficient. Both thestrikethrough and the wetback are measured in accordance with the testmethod described below. Comparatively speaking, higher performance inboth tests is achieved by a lower numerical result. In other words, thelower the amount of time required to absorb the fluid, the better thestrikethrough performance, and the lower the amount of fluid that iscollected at wetback, the better the wetback performance. Partitioncoefficient core is a measure of the percent of fluid retained in theabsorbent core of the absorbent article after strikethrough and rewettesting as described in test method described below. A higher partitioncoefficient core is preferred as it indicates that the fluid is notbeing retained in the topsheet and ADL layers or being released aswetback.

Simulated Menstrual Fluid Testing Intermediate Partition CoefficientLayer Strike Through(s) Wetback(g) Core (%) P&G 47.4 1.54 67 Type 1427.2 1.23 84 Type 15 22.6 1.74 79 Type 16 33.9 1.42 82

Saline Testing Intermediate Layer Strikethrough (s) Wetback (g) P&G 3.010.4 Type 14 2.12 0.22 Type 15 1.98 0.47 Type 16 1.69 0.41

As can be seen, all of the materials tested had better strikethroughperformance than the P&G ADL. Type 14 had better wetback performancethan the P&G ADL. Type 15 and type 16 had comparable wetback performancethan the P&G ADL. All of the tested materials had better partitioncoefficient core measures than the P&G ADL.

Strikethrough Wetback and Partition Coefficient Test Method

The test method below is used to determine the acquisition time(strikethrough), the rewet performance (wetback) and fluid distribution(partition coefficient) of constructed feminine hygiene products.

In general terms, a feminine hygiene product is dismantled and weighedin each layer (topsheet, acquisition distribution layer (ADL) andabsorbent core). The feminine hygiene product is reconstructed andinsulted with 10 ml of simulated menstrual fluid. The strikethrough timeis measured and recorded. After 20 minutes, 10 pre-weighted pick uppapers are placed onto the insulted region and 0.58 psi of pressure isapplied for 2 minutes. The pick-up papers are weighed again and theamount of rewet is calculated and reported in grams. The femininehygiene product is dismantled again and the parts are weighed again tocalculate the partition coefficient of each layer (% of liquid retainedin each layer). The following equipment is used in this test method:

-   -   50 ml capacity Burette with a supporting stand.    -   Strikethrough apparatus according to EDANA ERT 150.5-02        (including a funnel with magnetic valve, ring stand to support        the funnel, strikethrough plate with electrodes, base plate, and        electronic timer) sold under the name Lister by Lenzing Technik        of Austria.    -   Pickup paper (ERT FF3—STRIKETHROUGH/WETBACK) supplied by        Hollingworth & Vose Company Ltd. (UK).    -   Analytical balances (Accuracy of 0.001 g).    -   Weight of 4 Kg with a 100 mm×100 mm surface to provide 0.58 psi        load.

Testing Fluids

-   -   Saline Solution consisting of a 9,0 g/l solution of analytical        grade sodium chloride in deionised water with surface tension of        70±2 mN/m at 23±2° C.    -   Simulated menstrual fluid having a viscosity of 13 cps        (centipoises)±1 cps as measured at 25° C. and containing the        following ingredients listed as percentage by weight:

90.37% Water (H₂O)  7.50% Glycerin  1.13% Sodium Carboxymethyl Cellulose(CMC)  0.50% Sodium Chloride (NaCl)  0.40% Sodium Hydrogen Carbonate(NaHCO₃)  0.10% Ca24 - a commercially available anti-bacterial agent,sourced from Maycos Italia.

It is recommended that the test be conducted in a standard laboratoryenvironment with a temperature of 20° C.±2° C. and relative humidity of50%±5%. The specimen and pick-up paper should be conditioned for 24hours prior testing at 23° C.±2° C. and relative humidity of 50%±5%.

To begin testing, the feminine hygiene product is deconstructed. Thetopsheet, ADL and core (including the backsheet and other non-absorbentparts) are carefully detached from each other. Freezing agent (i.e.Check Spoilt supplied by Bieffe Chemical snc) can be locally applied onthe feminine hygiene product to inactivate the hot melt adhesive andassist in separating the layers when hot melt adhesive was used in theoriginal construction of the product. The test specimen should be cleanand free of edge tear, wrinkles and blemishes, which can contribute tofalse results. After separation, weigh the topsheet and the ADL andrecord the weights as T_(o) and ADL_(o), respectively. Additionally,weigh the remaining part of the feminine hygiene product, including thecore and backsheet and record the weight as Core_(o). The femininehygiene product is then carefully re-constructed to form an intactproduct.

Set up the ring stand holding the funnel and position the burette withthe tip inside the funnel. Place the strikethrough plate on the femininehygiene product with the product's acquisition side up and the center ofthe plate over the center of the product's insult point, near the middleof the product. Check that the electrodes in the strikethrough plate areclean. Adjust the height of the funnel to the top of the cavity in theplate. Ensure that the electrodes are connected to the timer. Activatethe timer and set the time to zero. Fill the burette with the simulatedmenstrual fluid. Keep the discharge valve of the funnel closed and run10 ml of simulated menstrual fluid from the burette to the funnel. Openthe magnetic discharge valve of the funnel to discharge the 10 ml ofsimulated menstrual fluid. Record the strikethrough time as displayed bythe timer. Gently remove the feminine hygiene product from thestrikethrough apparatus and leave it in a horizontal position for 20minutes to ensure even diffusion of the liquid.

Weigh 10 layers of dry pick-up paper, record the mass and place themover the insult point of the feminine hygiene product. Carefully applythe 4 kg weight onto the pick-up paper over the insulted point of thefeminine hygiene product and leave it in place for 2 minutes. Remove theweight and reweigh the pick-up papers. Detach each layer (topsheet, ADL,and core, as above) and weigh them to record T_(Fin), ADL_(Fin) andCore_(Fin), respectively. Repeat the test on at least two more femininehygiene products.

For each feminine hygiene product, calculate the Rewet using thefollowing formula:Rewet (g)=[Wet Weight of pickup paper (g)−Dry Weight of pickup paper(g)]

Evaluate the Partition Coefficient of each layer using the followingformula:

${{Partition}\mspace{14mu}{Coefficient}\mspace{14mu}{Topsheet}\mspace{14mu}(\%)} = {\frac{\left( {T_{Fin} - T_{o}} \right)}{\left( {Liquid}_{Discharged} \right)} \times 100}$${{Partition}\mspace{14mu}{Coefficient}\mspace{14mu}{ADL}\mspace{14mu}(\%)} = {\frac{\left( {{ADL}_{Fin} - {ADL}_{o}} \right)}{\left( {Liquid}_{Discharged} \right)} \times 100}$$\;{{{Partition}\mspace{14mu}{Coefficient}\mspace{14mu}{Core}\mspace{14mu}(\%)} = {\frac{\left( {{Core}_{Fin} - {Core}_{o}} \right)}{\left( {Liquid}_{Discharged} \right)} \times 100}}$Where:Liquid_(Discharged)=Rewet+(T _(Fin) −T_(o))+(ADL_(Fin)−ADL_(o))+(Core_(Fin)−Core_(o))

The above test method may also be conducted using 10 ml. of salinesolution in place of the 10 ml. of simulated menstrual fluid. When usingsaline, the pad is insulted with 10 ml. of saline solution andstrikethrough time recorded, as described above. The weight (0.58 psi)is placed onto the insulted region for 3 min. The weight is removed and10 pre-weighed pick up papers are placed onto the insulted region. Theweight is re-applied, providing 0.58 psi of pressure, for 2 min. Thepick up papers are weighed again and the amount of rewet is calculatedas described above.

Note that this test method is based on the following EDANA RecommendedTest Methods: ERT 150.5-02 “Liquid Strike-Through Time” and ERT 151.3-02“Wetback”.

CONCLUSION

A number of embodiments of the invention have been described.Nevertheless, it will be understood that various modifications may bemade without departing from the spirit and scope of the invention. Forexample, additional layers may be added to the absorbent article.Accordingly, other embodiments are within the scope of the followingclaims.

1. An absorbent article with a body facing side, the absorbent articlecomprising: a topsheet on the body facing side; a backsheet opposite thebody facing side; an absorbent core between the backsheet and thetopsheet; and a composite intermediate layer between the absorbent coreand the topsheet, said composite intermediate layer comprising: a firstnonwoven web of fibers; and an underlayer between the first nonwoven weband the absorbent core, said underlayer having small scale openings witha hydraulic radius; the first nonwoven web of fibers comprising aplurality of three dimensional conical large scale apertures extendingthrough both the nonwoven web and the underlayer, said large scaleapertures having a hydraulic radius that is substantially greater thanthe hydraulic radius of the small scale openings of the underlayer, andsaid large scale apertures not extending through the topsheet.
 2. Theabsorbent article of claim 1, wherein the underlayer comprises aresilient formed film having a male side and a female side opposite themale side.
 3. The absorbent article of claim 2 wherein the male side ofthe formed film faces the nonwoven web.
 4. The absorbent article ofclaim 1 wherein said large scale apertures are generally conical inshape, tapering from a larger opening to a smaller opening, the largeropening being between the smaller opening and the topsheet.
 5. Theabsorbent article of claim 4 wherein said large scale apertures havegenerally unconsolidated fibers near the larger opening and generallyconsolidated fibers near the smaller opening.
 6. The absorbent articleof claim 4 wherein fibers of said nonwoven web are bonded to theunderlayer at said smaller opening by melted portions of saidunderlayer.
 7. The absorbent article of claim 1 wherein the small scaleopenings in the underlayer have a mesh count between about 50/cm² andabout 100/cm².
 8. The absorbent article of claim 1 wherein the largescale apertures have a mesh count between about 6/cm² and about 11/cm².9. The absorbent article of claim 8 wherein the small scale openings inthe underlayer have a mesh count between about 10 and about 20 timesgreater than the mesh count of the large scale apertures.
 10. Theabsorbent article of claim 1 wherein the underlayer comprises stiffeningmeans.
 11. The absorbent article of claim 1, wherein the underlayercomprises a resilient three-dimensional apertured formed film and a meshcount of the large scale openings is less than a mesh count of the smallscale openings.